agx: Stub NIR backend compiler
A fork of the Bifrost compiler, tailored to AGX. nir_register support is
removed, as I want to use an SSA-based allocator for AGX. (There are no
VLIW-like requirements and extremely limited vector semantics, so we can
use an ACO approach with ease.)
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
Acked-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10582>